He worked as a reporter for Granada TV's 'World In Action', winning a Royal Television Society award in 1985, for a film about Northern Ireland.

For the Guardian he reported extensively on the mid-1990s war in Bosnia, particularly on the concentration camps in northwest Bosnia operated by the Bosnian Serbs for the incarceration of Muslim and Croat inmates at Omarska and Trnopolje. He also extensively covered the 9/11 attacks, while living in New York in 2001. At the outbreak of the current war in Iraq, in March 2003, he was one of the first reporters on the ground.

He was awarded Granada Television's Foreign Correspondent of the Year Award for 1992 and the James Cameron Award in 1994 and named Foreign Reporter of the Year in 1993 and 1997. In 2013, Vulliamy was awarded the coveted Ryszard Kapuscinski Award for Literary Reportage - named in honour of the great writer, creator and master of the genre - for 'Amexica: War Along the Borderline'.